Inflatable packers are used in the oil industry during testing, completion and workover operations to bridge a well bore or to isolate a zone therein. A typical inflatable packer has a tubular body that carries upper and lower retainer rings to which the adjacent ends of an inflatable packer element are attached. In response to the application of fluid pressure to the inside of the packer element, it expands outward into sealing engagement with the surrounding well bore well.
One type of inflatable packer element has an inner elastomer sleeve or bladder that is surrounded by an armor assembly which can be a plurality of circumferentially spaced, overlapped slats, reverse-layed cables, or a composite of woven materials such as cables or wires. An outer elastomer sleeve covers all or a part of the armor assembly to provide a leak proof seal with the well bore wall when the inner sleeve is pressurized and expanded. The end portions of the armor assembly extend underneath stress rings to where they are joined to retainer rings by welding. During operation of the packer at high differential pressures, each end portion of the armor has outer .edges that tend to indent the nose of its associates stress ring which can cause one or more small initial cracks to appear therein. Since the stress ring is very highly stressed normal to such indentations, the cracks tend to propagate and cause failure on the stress ring and thus the packer element. Thus such indentations can limit the operating differential pressure of the packer in an undesirable manner.
The general object of the present invention is to provide a new and improved inflatable packer of the type described having protectors which distribute the localized loads and thereby minimize indentations in the packer stress rings under high differential pressure operations.